Toro Decks

I purchased two new 62" Toro 200 series Z masters at the beginning of this season and think they are great mowers except that I have had identical problems with both decks after about 250 hrs. The spindle on the discharge side on both have moved up so that i have to shim the blades down about 3/16"in order to get an even cut. The center pully on both decks has sheared the splines within 40 hrs of each other. The dealer has been great and has repaired the machines quickly under warranty at no cost and no hassle.
He says he is talking to toro about problem. Has anyone else experienced anything similar.